Improvement in turning-lathes



UNITED STATES OFFICE.,

NATHAN HARPER, or NEWARK, N Ew JERsEY.

IMPROVEMENT iN TURNING-LATHES.

Specification forming part of Letters Patent No. 46,352; dated February14, 1865.

.To all whom, it may concern:

Be it known that I, NATHAN HARPER, of the city of Newark, in the countyot' Essex and State of New Jersey, have made certain Improvements inShaping-Lathes; and I do hereby declare the following to be a full andexact description ot' the same, reference being herein had to thedrawings that accompany this specification and make part of the same.

The nature of my improvement consists in a new arrangement, and in apeculiar construction by which is attained a degree of perfection inworkmanship neve-r before reached by any lathe of the kind now in use.

Figure l is a side view of a lathe embodying my invention.- Fig. 2 is aplan of the same, and Fig. 3 is a transverse section in the line a: a'.Fig. 4 is a diagram.

The same letters refer to the same parts in each figure.

The tool-post e on the sliding rest A isv constructed in partsyand w,the parts being held together by a groove and tongue, or in any othermanner that will secure' freedom ot' motion -to the part x, while itholds the tool lw firm and steady, free from any vibratory motion. Thepait y is fastened immovably to the sliding rest A, the resthaving onlyone movement, which is parallel with the centers of the piece beingturned. The part x has two movements, one with the sliding rest A andparallel with the center of the thing being turned, the other in a linevertical to the first, or upon any straight line radiating from thecenter of the piece that is being turned.

Pins o o project one on each side ofthe part x and rest on theshaping-bars or patterns B, and are held down thereon by the springs ss, the lower end ot' the springs being fast to the pins t t, that arefixed on the part z of thc tool-post.

One cuttingtool r is set in the part y, reducing the rough piece to anexact tit in the hole q-that is, through the upper partofy, as shown atFig. by which the piece being operated upon is held steady close to thetool w, keeping the same distance therefrom the whole length of theturning piece. The tool rmay operate at the top or any other part of thehole q., The distance of the cutting part of the said tool from the axisof the stuff determines the radius to which the latter is cut. It' atany time the patterns raise the tool w farther from the axis than thetool r, the effect is simply to leave that part of the turned piece ofthe full diameter to which itwas reduced by the first tool.

Fig. 3 shows the peculiar shape and the cutting position of the tools wand r. The shaving is taken mostly endwise of the turning piece, thesmooth cut being attained by the end or corner of the cutting gouge'projecting and being kept upon the turning piece on the straight lineradiating from the center, let its size be large or small, thus causingthe last of the shaving to be almost imperceptibly fine, so that themost knotty cross-grained wood can be turned equally smooth with theclearest and straightest, and to a less diameter than ever before couldbe done by a lathe with such cross-grained material.

In Fig. et is an illustration of the principle of moving a tool on acurved vertical line, which prevents the result attained by the toolmoving in a straight line radiating from the center. It will be seenthat when the turned piece is of the medium size p, Athe tool can restupon the wood back of the cutting-edge, and so preserve the eventhickness of a shaving; but if the turned piece is of the diameter at o,then the heel ofthe tool lifts the edge above a cutting position, and ifthe piece is reduced to the diameter at a, then the tool of necessity digs or scrapes instead of cutting. In Fig, 4 there is also shown theimpossibility of even a vertical straight-line movement of a tool beingalone a dependence for smooth turning so long as there is any of thefeature of the tools ie sting on the turm d picce back of the cutting,for if the tool m is shaped to rest on a piece ofthe diameter of o, itcannot fit a piece of the diameter of a, and must depend on the rigidityof its holder in toto for the degree of smoothness that may be attained.Itis only in the bearing of the tool upon the wood just forward from thecut direct uponthe stright line radiating from the ceilter of theturning piece that the uniform cut and polish from the cut can be had inany and every variety of diameters alike, or that can produce the samesmoothness upon crossgrained as upon straight-grained material, morefrom the cut than the friction.

' shaping bars or patterns. Lathes with slides carrying cutters whichall move in the same direction are common. vAll of" such I therefore, ofcourse, disclaim; but

What I do claim, and desire to secure, is- 1. The use of slides carryingcutters having free play in a plane at right angles to the axis of thestuft1 or thing being cut, in combination with springs and shaping bars.

2. The use of a compound sliding rest consisting` of a slide carrying acutter that moves in a straight line parallel with the center of thething being cut, in combination with a .slide (or slides) carrying acutter adapted to move in a plane at right angles to the axis of thethingbeing cut or shaped.

NATHAN HARPER.

Witnesses:

MORRIS B. LINDsLEY, W. M. GooDING.

